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// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_AUDIO_AUDIO_SYSTEM_H_
#define MEDIA_AUDIO_AUDIO_SYSTEM_H_
#include <string>
#include "base/callback.h"
#include "base/optional.h"
#include "media/audio/audio_device_description.h"
#include "media/base/audio_parameters.h"
#include "media/base/media_export.h"
namespace media {
// Provides asynchronous interface to access audio device information
class MEDIA_EXPORT AudioSystem {
public:
// Replies are sent asynchronously to the thread the calls are issued on.
// Instance is bound to the thread it's called on the first time.
// Attention! Audio system thread may outlive the client
// objects; bind callbacks with care.
// Non-empty optional AudioParameters are guaranteed to be valid.
// If optional AudioParameters are empty, it means the specified device is not
// found. This is best-effort: non-empty parameters do not guarantee existence
// of the device.
// TODO(olka,tommi): fix all AudioManager implementations to always report
// when a device is not found, instead of returning sub parameter values.
// Non-empty optional matched output device id is guaranteed to be a non-empty
// std::string. If optional matched output device id is empty, it means there
// is no associated output device.
using OnAudioParamsCallback =
base::OnceCallback<void(const base::Optional<AudioParameters>&)>;
using OnDeviceIdCallback =
base::OnceCallback<void(const base::Optional<std::string>&)>;
using OnInputDeviceInfoCallback =
base::OnceCallback<void(const base::Optional<AudioParameters>&,
const base::Optional<std::string>&)>;
using OnBoolCallback = base::OnceCallback<void(bool)>;
using OnDeviceDescriptionsCallback =
base::OnceCallback<void(AudioDeviceDescriptions)>;
virtual ~AudioSystem() = default;
virtual void GetInputStreamParameters(const std::string& device_id,
OnAudioParamsCallback on_params_cb) = 0;
virtual void GetOutputStreamParameters(
const std::string& device_id,
OnAudioParamsCallback on_params_cb) = 0;
virtual void HasInputDevices(OnBoolCallback on_has_devices_cb) = 0;
virtual void HasOutputDevices(OnBoolCallback on_has_devices_cb) = 0;
// Replies with device descriptions of input audio devices if |for_input| is
// true, and of output audio devices otherwise.
virtual void GetDeviceDescriptions(
bool for_input,
OnDeviceDescriptionsCallback on_descriptions_cb) = 0;
// Replies with an empty optional if there is no associated output device
// found and a non-empty string otherwise.
virtual void GetAssociatedOutputDeviceID(
const std::string& input_device_id,
OnDeviceIdCallback on_device_id_cb) = 0;
// Replies with audio parameters for the specified input device and
// device ID of the associated output device, if any (otherwise
// the associated output device ID is an empty optional).
virtual void GetInputDeviceInfo(
const std::string& input_device_id,
OnInputDeviceInfoCallback on_input_device_info_cb) = 0;
// This function wraps |callback| with a call to
// AudioDeviceDescription::LocalizeDeviceDescriptions for convenience. This is
// typically used by AudioSystem implementations, not AudioSystem clients.
static OnDeviceDescriptionsCallback WrapCallbackWithDeviceNameLocalization(
OnDeviceDescriptionsCallback callback);
};
} // namespace media
#endif // MEDIA_AUDIO_AUDIO_SYSTEM_H_
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